I'm a kit scrapper (exceptions are a challenge that requires mashing kits together, or as you said, pulling 1 or 2 things to throw on a page). The reason is pure Laziness on my part..... a lot of times I have a hard time remembering the name of the template I used by the time I'm done with a layout and I spend a lot of time looking for it in my stash so I can give the proper credits.... I can't imagine how scatter brained I'd be tracking a lot of different kits too.